CVE-2025-26682 in ASP.NET Core
Summary
by MITRE • 04/08/2025
Allocation of resources without limits or throttling in ASP.NET Core allows an unauthorized attacker to deny service over a network.
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Analysis
by VulDB Data Team • 10/25/2025
This vulnerability represents a critical resource management flaw in ASP.NET Core applications that enables unauthorized attackers to perform denial of service attacks through uncontrolled resource consumption. The issue stems from insufficient limits and throttling mechanisms within the framework's resource allocation processes, creating opportunities for malicious actors to exhaust system resources and render services unavailable to legitimate users. The vulnerability specifically affects applications that rely on ASP.NET Core's default resource handling behaviors without implementing additional protective measures.
The technical root cause of CVE-2025-26682 lies in the absence of proper resource constraints within the ASP.NET Core runtime environment. When applications process incoming requests, they allocate various system resources including memory, file handles, and thread pools without adequate bounds checking or rate limiting controls. This allows attackers to craft malicious requests that consume excessive resources, potentially leading to memory exhaustion, thread pool starvation, or other resource depletion conditions that prevent legitimate operations from completing successfully. The flaw operates at the application level where resource management decisions are made, rather than at the infrastructure level where traditional rate limiting might occur.
From an operational perspective, this vulnerability presents significant risk to web applications that handle untrusted input or operate in environments where malicious actors may have access to the network. Attackers can exploit this weakness by sending multiple concurrent requests or by crafting requests that consume disproportionate amounts of system resources. The impact extends beyond simple service interruption to potentially affecting system stability, application performance, and overall availability of the affected services. Organizations running ASP.NET Core applications without proper resource management controls are particularly vulnerable to this type of attack.
The vulnerability aligns with CWE-770, which addresses allocation of resources without limits or throttling, and can be mapped to ATT&CK technique T1499.004 for network denial of service attacks. Organizations should implement comprehensive resource management strategies including request throttling, connection limits, memory usage monitoring, and proper error handling to prevent exploitation. Mitigation strategies include configuring appropriate limits in application settings, implementing rate limiting middleware, deploying application firewalls, and establishing monitoring systems to detect unusual resource consumption patterns. Regular security assessments and code reviews should focus on resource allocation patterns to identify potential vulnerabilities before they can be exploited by attackers.
Security teams should prioritize patching affected ASP.NET Core versions and implementing additional protective controls beyond the default framework behavior. The vulnerability demonstrates the importance of defense in depth approaches where multiple layers of protection work together to prevent resource exhaustion attacks. Organizations must also consider implementing automated scaling mechanisms and load balancing strategies to distribute requests and reduce the impact of individual malicious requests on overall system availability. Proper logging and alerting configurations are essential to detect exploitation attempts and respond quickly to potential attacks targeting resource consumption patterns.